Subject: Re: [RFC PATCH net-next v6 4/4] netvsc: refactor notifier/event handling code to use the bypass framework

From: "Michael S. Tsirkin" <[email-masked]>
Date: Wed, 11 Apr 2018 02:28:51 +0300

On Tue, Apr 10, 2018 at 02:26:08PM -0700, Stephen Hemminger wrote:
> On Tue, 10 Apr 2018 11:59:50 -0700
> Sridhar Samudrala <[email-masked]> wrote:
> 
> > Use the registration/notification framework supported by the generic
> > bypass infrastructure.
> > 
> > Signed-off-by: Sridhar Samudrala <[email-masked]>
> > ---
> 
> Thanks for doing this.  Your current version has couple show stopper
> issues.
> 
> First, the slave device is instantly taking over the slave.
> This doesn't allow udev/systemd to do its device rename of the slave
> device. Netvsc uses a delayed work to workaround this.

Interesting. Does this mean udev must act within a specific time window
then?

> Secondly, the select queue needs to call queue selection in VF.
> The bonding/teaming logic doesn't work well for UDP flows.
> Commit b3bf5666a510 ("hv_netvsc: defer queue selection to VF")
> fixed this performance problem.
> 
> Lastly, more indirection is bad in current climate.
> 
> I am not completely adverse to this but it needs to be fast, simple
> and completely transparent.